The book's primary goal is to provide an identification guide to the geometroid caterpillars of eastern forests, the authors' hope is the volume will provide greater appreciation for the rich and varied biodiversity found in forests of the United States and Canada, and serve as a reminder that proportionately few caterpillars are pests. Most caterpillars, by virtue of their importance in food webs and nutrient cycling, are benefical. The book endeavors to show that many forest caterpillars are fascinating and, not uncommonly, visually beautiful subjects.